How to Read and Remember Resistor Color Codes | Which End to Start From, 4-Band vs 5-Band, Color Chart, Common Values and Colors That Are Easy to Mix Up

The short answer: gold or silver band on the right, then read “digit, digit, multiplier, tolerance” from the left

The resistor color code is the method, defined in the international standard IEC 60062 (JIS C 60062 in Japan), for showing a resistance with colored bands. For the most common 4-band resistor, four steps are enough.

1. 1

   Decide which way round it goes

   Put the gold or silver band (the tolerance band) on the right. The tolerance band is usually printed a little apart from the others, so you can also put the side with the wider gap on the right.

2. 2

   Read the two left bands as digits

   Turn the first and second colors into digits to make a two-digit number. Yellow (4) and violet (7) give 47.

3. 3

   Add as many zeros as the third band's number

   The third band is the multiplier. Red (2) means adding two zeros: 4,700 Ω = 4.7 kΩ. Gold means ×0.1 and silver ×0.01; they are used on resistors below 10 Ω.

4. 4

   Read the tolerance from the fourth band

   Gold is ±5%, silver ±10% and brown ±1%. Any deviation from the marked value within this percentage is normal.

A 5-band resistor simply has one more digit band, giving “digit, digit, digit, multiplier, tolerance”; the idea is the same. The steps are simple, but with real parts it is easy to go wrong over which end is the right-hand one or whether a band is brown or red, so the sections below go through these in order.

Chart of colors, digits, multipliers and tolerances

The color code uses 12 colors. The same color means different things depending on whether it sits in a digit band, the multiplier band or the tolerance band.

For the multiplier, remember “add as many zeros as the color's digit” and you can read it without the chart: black adds none (×1), brown adds one (×10), red two (×100) and orange three (×1,000). The 2016 edition of IEC 60062 gives grey a tolerance of ±0.01%, but older references list ±0.05%. In hobby electronics you will almost never see grey or white as a multiplier or tolerance.

How to remember it: 2 to 7 follow the rainbow, with black 0 and brown 1 before and grey 8 and white 9 after

The most reliable way to memorize the colors for 0 to 9 is the rainbow. Digits 2 to 7 are red, orange, yellow, green, blue and violet, exactly the order of the colors in a rainbow (indigo is not used in the resistor code).

• 0 black: no color at all, so zero
• 1 brown: between black and red, on the way from dark to bright
• 2–7 red, orange, yellow, green, blue, violet: the rainbow order
• 8 grey: between violet and white, a mix of black and white
• 9 white: the brightest color comes last

In other words, the colors run from dark to light: black, brown, the six rainbow colors, grey, white. If you prefer a sentence, there are many mnemonics whose initial letters match the colors. A widely quoted one is “Bad Beer Rots Our Young Guts But Vodka Goes Well”.

For tolerance, learning just gold ±5% and silver ±10%, plus brown ±1% and red ±2% (common on 5-band precision resistors), lets you read almost any resistor in your box. Brown ±1% and red ±2% match the digits brown 1 and red 2, so they are easy to remember. One mnemonic is plenty; after reading a few resistors, frequent combinations such as brown-black (10) and yellow-violet (47) start to jump out at you as color pairs.

Which end do you read from? Telling the direction, and the trap where the backwards reading also works

The first stumbling block with color codes is direction. A resistor has no marked left or right, so depending on how you pick it up you may read it backwards. Check the following in order.

• Gold and silver go on the right: gold and silver are never digits (they cannot be the first or second band), so the side with gold or silver is the tolerance end, on the right
• The wider gap goes on the right: the tolerance band is often printed slightly apart from the others
• The bunched-up side is the left: the first band is often closer to the lead
• The first band is never black: no value starts with 0, so if you start with black, suspect you are reading backwards
• A value outside the E series is suspicious: resistor values come from a fixed set of numbers (the E series, see below), so if your reading isn't in it, you have probably got the direction or a color wrong

With a 4-band resistor that has a gold or silver band, the direction is rarely in doubt. Read brown-black-orange-gold (10 kΩ ±5%) backwards and the first band is gold, which cannot be read as a digit at all. The trouble comes with 5-band resistors whose tolerance is brown (±1%) or red (±2%). Both ends can be brown, and the code can make sense read either way.

In the first three rows, the backwards readings of 120 Ω, 110 Ω and 10 kΩ are all real standard values, so the “not in the E series means backwards” rule doesn't help. Misreading a 10 kΩ resistor (brown-black-black-red-brown) as 120 Ω could send over 80 times as much current through an LED and destroy it. For 5-band resistors like these, look closely at the band spacing, and if in doubt measure with a multimeter. When the backwards reading gives something like 1.1 GΩ, as in the fourth row, a value you would never use in hobby electronics, you can safely decide it is backwards.

4-, 5-, 6- and 3-band resistors: the differences and how to read them

Whatever the number of bands, the order from the left is always digits → multiplier → tolerance. What changes is how many digits there are and whether a temperature coefficient band is added at the end.

• 3 bands: no tolerance band, meaning ±20%. You see these on old parts or where precision doesn't matter
• 4 bands: the ordinary resistor, mostly ±5% (gold). With two significant digits it can show values up to the E24 series
• 5 bands: three significant digits, so it can show fine E96 values such as 1.02 kΩ and 4.99 kΩ. Common on ±1% metal film resistors
• 6 bands: a band after the five shows how many ppm (parts per million) the resistance changes for each 1 °C (1 K) change in temperature. Brown, 100 ppm/K, means up to 0.1% change for a 10 °C rise

A 5-band 10 kΩ resistor is brown-black-black-red because its three significant digits are 100, multiplied by ×100 (red). A 4-band 10 kΩ has significant digits 10 and multiplier ×1,000 (orange), so the multiplier color shifts by one for the same value. Reading a 5-band resistor as if it had 4 bands throws the value way off, so count the bands before you start. A resistor with a single black band is a 0 Ω resistor (used in place of a jumper wire).

Color code chart for common resistor values (10 Ω to 1 MΩ)

These are the color codes for values often used in hobby electronics. On both 4-band and 5-band resistors, one more tolerance band follows (usually gold ±5% on 4-band and brown ±1% on 5-band).

Laid out like this, you can see that the first two bands are nearly always one of four pairs, brown-black (10), red-red (22), orange-orange (33) and yellow-violet (47), and the third band gives the decade. After brown-black, brown means 100 Ω, red 1 kΩ, orange 10 kΩ and yellow 100 kΩ: each step along the multiplier colors is ten times more.

Why is it always 4.7 kΩ and 2.2 kΩ? How the E series works

The resistors on sale come in values that look oddly specific, such as 1 kΩ, 1.2 kΩ and 1.5 kΩ, and round values like 5 kΩ are hard to find. That is because resistances are chosen from a standard sequence of numbers called the E series. The E12 series divides each decade from 1 to 10 into 12 steps at a nearly constant ratio (about 1.2 times each).

The values are spaced by ratio so that the tolerance ranges join up without gaps. In the E12 series, for example, 4.7 kΩ ±10% covers 4.23–5.17 kΩ and the next value, 5.6 kΩ ±10%, covers 5.04–6.16 kΩ, so the ranges overlap slightly. A manufacturer can measure each resistor and sell it as whichever value it falls under, so almost nothing has to be thrown away.

This also gives you a check when reading color codes. If a 4-band resistor reads as 4.6 kΩ or 5.0 kΩ, values not in the E24 series, you have most likely misread a color. If you need 5 kΩ, substitute the E24 value of 5.1 kΩ or connect two 10 kΩ resistors in parallel.

Telling easily confused colors apart: brown vs red, gold vs orange, grey vs white and silver

Color codes are printed as thin bands on small parts, and the shades vary with the manufacturer and the lighting, so most misreadings come from judging colors. Here are the pairs that are easy to mix up and how to check them.

• Under warm (orange-tinted) light, brown, red and orange are hard to tell apart. Look under neutral white light or daylight
• Zooming in with a smartphone camera makes the band edges clearer. Photo colors can differ from the real thing, though, so judge the colors on the part itself where you can
• If you have several resistors from the same bag, lining them up makes it easier to see which bands are brown and which are red
• Check your reading against the E series and against the value on the schematic

Depending on your color vision, red, brown and green can be hard to distinguish. In that case, too, don't force a judgment by color; measuring with a multimeter is the most reliable way. When you store resistors, writing the value on the bag or compartment saves you reading them again next time.

What to watch out for when checking with a multimeter

If you are unsure of a color code, measuring on the resistance (Ω) range of a multimeter settles it. Measure the wrong way, though, and you won't get the right value.

1. 1

   Take it out of the circuit

   While it is soldered to a board, the meter also measures current flowing through other parts and shows a lower value than the real one. Measure a new resistor, or one with one lead lifted.

2. 2

   Don't hold both ends with your fingers

   Pinching both ends of the resistor together with the probes puts your body's resistance in parallel. On large values above about 100 kΩ, the reading can come out noticeably low. Hold only one side, or clip it with crocodile clips.

3. 3

   Check that it is within the tolerance

   If a 4.7 kΩ ±5% resistor shows 4.68 kΩ, it is fine. It will almost never read exactly the marked value, so if it is within the tolerance range (4.465–4.935 kΩ), your color reading is correct.

If the measured value is far outside the tolerance and off by a neat ratio such as ten times or one tenth, you have probably misread the multiplier band. If it is off by around double, suspect a misread digit band, such as brown vs red.

Checking with the Resistor Color Code Calculator

With the Resistor Color Code Calculator you can check a resistance just by tapping the band colors, and look up the color code for a value the other way round.

1. 1

   Choose the number of bands in “Colors to ohms”

   Pick 4, 5, 6 or 3 bands to match the resistor in your hand.

2. 2

   Tap the colors starting from the left band

   With the gold or silver band on the right, choose the colors from the left. The resistor drawing takes the same colors so you can compare it with the real part, and the resistance, tolerance and actual range appear straight away.

3. 3

   Check the reverse reading

   When the first band is black, or when your reading isn't in the E series but the reverse reading is, the backwards value is shown. Press “Swap left and right” to switch to the reverse reading.

4. 4

   Look up colors from a value

   Enter a value like 4.7k, 4k7 or 10k on the “Ohms to colors” tab to get the 4-band and 5-band colors and the nearest values above and below in the E12, E24 and E96 series. Handy for finding the resistor you need in a parts box.

Markings such as 103, 4R7 or 01C printed on small rectangular parts on a board (SMD resistors) can be decoded on the “SMD resistor codes” tab, the value and wattage of a resistor for an LED on the “LED resistor” tab, and combinations of two resistors that make the value you want on the “Series, parallel & combos” tab. The power a resistor dissipates (its wattage) is voltage × current, the same idea as the electricity cost of a home appliance. The relationship between W and kWh is explained in How to Calculate Electricity Costs.

FAQ

Which end of a resistor color code do you read from?

Put the gold or silver band (the tolerance band) on the right and read from the left band. The tolerance band is usually set a little apart from the others, so put the wider gap on the right. The first band is never black, so if you start with black you are reading it backwards. A 5-band resistor with brown at both ends can make sense either way, so if in doubt measure it with a multimeter.

How do you remember the resistor color code?

The easiest way is to note that 2 to 7 follow the rainbow (red 2, orange 3, yellow 4, green 5, blue 6, violet 7), with black 0 and brown 1 before them and grey 8 and white 9 after. You can also think of it as running from dark to light. Sentence mnemonics such as “Bad Beer Rots Our Young Guts But Vodka Goes Well” work too.

What value is a brown, black, red, gold resistor?

Brown 1 and black 0 make 10, and red is ×100, so it is 1,000 Ω (1 kΩ) with gold ±5%. The real value falls between 950 Ω and 1,050 Ω. Brown-black-orange-gold is 10 kΩ and brown-black-yellow-gold is 100 kΩ.

What is the difference between 4-band and 5-band resistors?

The number of digit bands. A 4-band resistor has two digits + multiplier + tolerance and is usually ±5%. A 5-band resistor has three digits + multiplier + tolerance, so it can show fine values like 1.02 kΩ, and is used for ±1% precision resistors. Even for the same 10 kΩ, the colors differ: brown-black-orange on 4 bands, brown-black-black-red on 5 bands.

What is the color code for 4.7 kΩ?

On 4 bands, yellow-violet-red plus a tolerance band (gold for ±5%); on 5 bands, yellow-violet-black-brown plus a tolerance band (brown for ±1%). Yellow 4 and violet 7 make 47, and red is ×100, giving 4,700 Ω.

How do you read a gold third band?

Gold in the third (multiplier) position is ×0.1, and silver is ×0.01. Brown-black-gold-gold is 10 × 0.1 = 1 Ω ±5%, and red-red-silver-gold is 22 × 0.01 = 0.22 Ω ±5%. They are used on resistors below 10 Ω.

I can't tell brown and red bands apart.

They are hard to distinguish under warm light, so compare them with the other bands on the same resistor under neutral white light or daylight. Also check whether your reading is in the E series (for E24: 1.0, 1.1, 1.2, 1.3, 1.5 …). If you are still unsure, measuring with a multimeter is the reliable answer.

My multimeter reading doesn't match the marked value.

Within the tolerance it is normal: a 1 kΩ ±5% resistor is fine anywhere from 950 Ω to 1,050 Ω. Measuring it on the board or holding both ends with your fingers gives a lower value than the real one. If it is off by ten times or one tenth, you have misread the multiplier band.